tty.go (2836B)
1 // Copyright 2021 The TCell Authors 2 // 3 // Licensed under the Apache License, Version 2.0 (the "License"); 4 // you may not use file except in compliance with the License. 5 // You may obtain a copy of the license at 6 // 7 // http://www.apache.org/licenses/LICENSE-2.0 8 // 9 // Unless required by applicable law or agreed to in writing, software 10 // distributed under the License is distributed on an "AS IS" BASIS, 11 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 12 // See the License for the specific language governing permissions and 13 // limitations under the License. 14 15 package tcell 16 17 import "io" 18 19 // Tty is an abstraction of a tty (traditionally "teletype"). This allows applications to 20 // provide for alternate backends, as there are situations where the traditional /dev/tty 21 // does not work, or where more flexible handling is required. This interface is for use 22 // with the terminfo-style based API. It extends the io.ReadWriter API. It is reasonable 23 // that the implementation might choose to use different underlying files for the Reader 24 // and Writer sides of this API, as part of it's internal implementation. 25 type Tty interface { 26 // Start is used to activate the Tty for use. Upon return the terminal should be 27 // in raw mode, non-blocking, etc. The implementation should take care of saving 28 // any state that is required so that it may be restored when Stop is called. 29 Start() error 30 31 // Stop is used to stop using this Tty instance. This may be a suspend, so that other 32 // terminal based applications can run in the foreground. Implementations should 33 // restore any state collected at Start(), and return to ordinary blocking mode, etc. 34 // Drain is called first to drain the input. Once this is called, no more Read 35 // or Write calls will be made until Start is called again. 36 Stop() error 37 38 // Drain is called before Stop, and ensures that the reader will wake up appropriately 39 // if it was blocked. This workaround is required for /dev/tty on certain UNIX systems 40 // to ensure that Read() does not block forever. This typically arranges for the tty driver 41 // to send data immediately (e.g. VMIN and VTIME both set zero) and sets a deadline on input. 42 // Implementations may reasonably make this a no-op. There will still be control sequences 43 // emitted between the time this is called, and when Stop is called. 44 Drain() error 45 46 // NotifyResize is used register a callback when the tty thinks the dimensions have 47 // changed. The standard UNIX implementation links this to a handler for SIGWINCH. 48 // If the supplied callback is nil, then any handler should be unregistered. 49 NotifyResize(cb func()) 50 51 // WindowSize is called to determine the terminal dimensions. This might be determined 52 // by an ioctl or other means. 53 WindowSize() (WindowSize, error) 54 55 io.ReadWriteCloser 56 }